NEW HAVEN (AP) — New Haven officials declared a public health emergency Friday after nearly 20 people overdosed on tainted heroin or cocaine and at least three died in the city and surrounding towns.

Officials said there had been up to 16 heroin or cocaine overdoses in New Haven since Thursday and several more in surrounding communities. Two people died in New Haven and at least another died in another town.

Officials said the numbers will likely rise and they pleaded with drug users to be careful.

Police were trying to determine if the powerful painkiller fentanyl or another substance played a role in the overdoses. Patients who were able to speak with city police said they thought they had bought cocaine and not heroin, Officer David Hartman said.

Police, fire officials and the federal Drug Enforcement Administration were working to arrange quick testing of seized drugs.

Most of the overdoses in New Haven were in the city's Newhallville/Dixwell community. Cases also were reported in West Haven and Shelton, Hartman said.

State health officials were sending 700 doses of the overdose reversing drug Narcan to New Haven, where officials said there was a shortage of the drug

Gov. Dannel P. Malloy called the situation dangerous.

"Everyone must recognize that no region of the country, state, city or town is immune — this affects all of us and so many families across our state and nation," the Democratic governor said in a statement. "That's why we have been doing everything in our power to stop this epidemic and prevent tragedy."

The medical examiner's office reports that 208 people died of accidental drug overdoses in Connecticut from January to March and projects the year-end total will be around 832, up from 729 last year and more than double the total from 2012.

U.S. Sens. Richard Blumenthal and Chris Murphy called on Congress to provide more resources to fight overdoses nationwide.

"Congress must reverse its laggard response to this national public health crisis by providing real resources," Blumenthal said. "Not only Narcan ... but treatment services, law enforcement support, opioid over-prescription prevention and other steps are urgent and critical."